ALSI was established in 1979 in association with an engineering and consulting firm, Skelly & Loy, Inc., located in Harrisburg, Pennsylvania. ALSI was later purchased in 1991 to become an independently owned and operated environmental services testing laboratory. As the laboratory began to expand and move into other areas of analytical testing such as industrial hygiene, ALSI considered purchasing a bigger facility to meet the demands of their clients and pursue larger environmental projects. In October 1997, ALSI purchased an environmental testing laboratory already established in the environmental testing industry. This acquisition was led by Michael S. Farlling, ALSI's President. In January of 2001, ALSI expanding the building by adding approximately 1,250 square feet to allow growth in the organic testing department. In April of 2004, ALSI made a second company acquistion by purchasing the assets of BH Laboratory owned by Pace Resources. This purchase enabled ALSI to obtain a market share centered in York while also providing ALSI an overflow option for excess work received in Middletown. In January 2007, ALSI completed another, and much larger building expansion. The 1.4 million dollar investment doubled the size of the facility which was starting to burst at the seams due to the growth in sales. In July of 2009, ALSI opened a Service Center in Eddison, NJ to accomodate and coordinate the expanding NJ and NY markets.